The Earth moves around the Sun in an elliptical orbit, not a perfect circle.

Here's why:

* Gravity and Inertia: The Earth's orbit is a result of the balance between the Sun's gravitational pull and the Earth's inertia (tendency to move in a straight line).

* Elliptical Shape: This balance creates an elliptical path, where the Earth is sometimes closer to the Sun (perihelion) and sometimes farther away (aphelion).

* Not a Perfect Circle: While the Earth's orbit is close to circular, it's not perfectly round. The eccentricity of Earth's orbit is relatively small, which means the ellipse is quite close to a circle.